1. Field of the Invention
The invention relates to an ice making system for a refrigerator and more particularly to an ice level sensing system for an ice maker.
2. Description of Related Art
Automatic ice making systems for use in a home refrigerator are well known. Typically, ice making systems include an ice maker mounted within the freezer compartment of the refrigerator and an ice storage receptacle or bin supported beneath the ice maker for receiving the formed ice from the ice maker. The ice maker is commonly mounted within the freezer compartment adjacent the side or rear wall of the freezer compartment such that water and power can be readily supplied to the ice maker. The ice storage receptacle is supported by a shelf structure beneath the ice maker within the freezer compartment. The ice storage receptacle generally extends across the freezer compartment and has a front end adjacent the freezer door. U.S. Pat. No. 4,942,979, to Linstromberg et al. is an example of a prior art ice making system.
In the design of ice maker systems for refrigerators, it is recognized that a control system must be provided for sensing the level of ice disposed in the ice storage bin such that ice pieces are produced when insufficient ice is in the storage bin and ice pieces are not produced when the ice storage bin is filled. A typical ice level sensing system, illustrated by U.S. Pat. No. 5,160,094, to Willis et al., includes an ice maker which employs a bail arm which is periodically lowered into the ice storage bin and then raised back out of the ice storage bin. If the presence of ice pieces interferes with the bail arm being lowered into the ice storage bin, the ice maker is deenergized such that more ice pieces are not produced.
Conventional ice level sensing systems such as the one disclosed by Willis et al. are not easily applied to a refrigerator ice making system having a door mounted ice storage bin. Door mounted ice storage bins offer several advantages--including making more space available for freezer shelving. However, if a conventional bail arm type ice level sensing system is used with a door mounted ice storage bin, damage may readily occur to the bail arm if the refrigerator door is opened when the bail arm is being lowered into the ice storage bin.
U.S. Pat. No. 3,635,043, to Sterling, is directed to a refrigeration system including a door mounted ice storage receptacle. Sterling discloses having a photoelectric system--employing an incandescent lamp 54 and a photocell 55--for sensing the level of ice in the door mounted bin. The lamp 54 is continuously on and shines a light beam across an ice storage bin. When the beam of light is interrupted by accumulated ice, ice harvesting is prevented.
One problem that exists with door mounted ice storage bins is untimely dispensing of ice pieces when the freezer door is open. Accordingly, for door mounted ice bin systems, some means must be provided for preventing the discharge of ice pieces when the freezer door is opened.
Another issue, common to all ice makers used in refrigerators, is the provision of a convenient on/off switch. It is desirable to have a convenient on/off switch such that the ice making system can be disabled during long periods of non-use.
Accordingly, there is a need for robust and effective ice maker control system which may be conveniently employed to sense the level of ice in an ice storage receptacle. In particular, there is a need for a simple and effective ice level sensing system for use with a door mounted ice storage bin.